Birds on the African-Eurasian flyway are disappearing. Despite cross-continental governmental co-operations protecting both their winter breeding and summer feeding grounds, these massive aerial migrations continue to dwindle. Many birds are dying somewhere in between, in unregulated areas in the Arabian Peninsula, where as many as 4.6 million are shot from the skies every year. Protected areas can’t save migratory species who leave their boundaries.
Photo by Jean Wimmerlin on Unsplash
As above, so below. For as long as humans have sailed, they have made laws to protect marine life, but the high seas have always existed beyond the realm of regulation… until now. With the United Nations’ ratification of the High Seas Treaty, a formal framework has been laid to establish marine reserves in international waters – and we need it, because just like the birds, the fish are disappearing.
While many experts agree that all high seas fishing should be banned, the negotiation of international marine protected areas – or MPAs – promises to be a contentious, byzantine process. Yet marine biologists and UN delegates hold hope that they may offer refuge for remote and imperiled reaches of our ocean like the Emperor Seamounts, the Gulf of Guinea, the Mascarene Plateau, and the Nazca Ridge. But the fisheries industry is seeking to poison the well by twisting the science to cast doubt on the efficacy of marine reserves.
Continuing their relentless communications crusade against MPAs, industry-aligned scientists have seized upon a new study to assert that marine reserves don’t work. Anti-MPA messaging has throttled up in outlets like Sustainable Fisheries UW, which receives significant financing from seafood corporations and shared its interpretation of the paper nine times across its social media leading up to and during High Seas Treaty negotiations. The research is not only ill-suited to assess the efficacy of MPAs, but also misrepresented by the commentary.
The study, published January 10 in Frontiers in Marine Science, models the impacts of three hypothetical no-take marine reserves on two highly migratory species – Pacific skipjack and bigeye tuna. Its outputs predict that extending Kiribati’s Phoenix Islands Protected Area into high seas areas would provide a modest boost to tuna populations. While its authors conclude “large oceanic MPAs are not likely to be effective frontline management tools for tropical tunas and other species having similar life history characteristics” [emphasis added], coverage in industry publications has run with headlines like, “MPAs just move fishing pressure.”
However, while understanding animal behavior is critical, so is design. If the aim is to protect tuna, the MPAs in these models are poorly planned – delineated as arbitrary rectangles, without consideration for oceanographic currents and migratory patterns of the tuna species whose populations it models.
The three hypothetical protected areas modelled by Hampton, et al. 2023 outlined in red – basic rectangles not based on tuna life cycles.
In addition, while analyses based purely on modeling have been cautioned against by various experts in the literature – in cases, explicitly for deep-diving species like tuna – the SEAPODYM model used by the researchers actually shows modest increases in spawning biomass, despite stable catch rates. On land, we would consider that a decent outcome. And while these models look okay, empirical observations to the north of Kiribati have shown massive increases in tuna populations spilling over into areas outside of the Hawai’ian Papahānaumokuākea Marine National Monument – the world’s largest marine reserve.
Predictably, this research has become the latest target of Sustainable Fisheries UW, who argues that increases in tuna were coincidentally driven by El Niño. While they make a fair case for different mathematical methods, other arguments put forward in their publication demonstrate the myopic single-species paradigm that plagues fisheries science. Furthermore, they miss the point: the sanctuary was designed to protect marine life inside its boundaries.
There are many other reasons to protect tuna beyond simply eating more of them. We now understand that tuna hunt in packs, using complex formations to drive schools of small prey fish from the depths to the surface. Tuna thus play a major role in generating the great open ocean feeding frenzies where seals, dolphins, sharks, and whales hunt alongside one another, a critical engine of the ecosystem – making tuna a keystone species. And of course, like all wildlife, tuna have inherent value.
In 2019, a groundbreaking study of the Phoenix Islands Protected Area showed three consecutive spawn years for three different tuna species within the reserve – the first evidence of highly migratory species spawning in marine sanctuaries. And in 2020, another found exceptional resilience of Kiribati corals to climate-induced bleaching, especially in locations where human impacts like fishing were limited, signaling a rare beacon of hope for the survival of coral reefs – if we protect them.
Sadly, the Phoenix Islands Protected Area, once the world’s largest fishing exclusion zone, has now lost most of its protection. After just six years, the Kiribati government decided it could not viably maintain the sanctuary due to the economic loss from decreased fishing licenses, which comprise over 70 percent of the island nation’s total revenue. These costs were supposed to be offset by a philanthropy-funded compensation scheme that didn’t deliver and the reserve is set to reopen to industrial purse-seiners. The new modeling study – coauthored by the Licensing Director of the Kiribati Ministry of Fisheries and financed by regional fishing powers like Australia and New Zealand – is being cited as justification.
While the High Seas Treaty will not resolve every issue facing our open oceans, it is a significant step toward progress. The establishment of internationally-protected areas can act as an important tool for protecting critical habitats like seamounts and migration corridors. UN member states should evaluate the efficacy of MPAs in protecting ecosystems as a whole as they negotiate regulation of activity on the high seas. In this respect, they have a proven track record.
It is true, however, that marine reserves have shortcomings, specifically in their potential to protect highly migratory species like tunas. Yet this is not a reason to reject them, but rather to supplement them with measures like careful planning – both ecological and economic; tighter regulations – on catches, labor, and markets; stronger sovereignty of island nations to diversify their economies and enforce their laws; and a deeper cultural appreciation for tuna as keystone species and charismatic megafauna in pelagic ecosystems.